With high integration in semiconductor devices, the channel length of a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) becomes increasingly shorter. Those effects that are negligible in a long-channel model of MOSFET become more significant, or even a major factor affecting the performance of the device. This phenomenon is called a short-channel effect. The short-channel effect may degrade electrical performance of the device, causing problems such as decreased threshold voltage of the gate, increased power consumption and reduced signal-to-noise ratio.
In order to control the short-channel effect, improvements have been made to conventional transistor devices in some aspects. However, with the channel size continuing to shrink, the improvements can no longer resolve the short-channel effect when it becomes increasingly significant.
Therefore, in order to solve the problem of short-channel effect, a three-dimensional device structure of Fin Field-Effect Transistor (FinFET) has been proposed. A FinFET is a transistor with a fin-shaped channel structure, in which some surfaces of a thin tin act as the channel, allowing enhanced operating current, and thus avoiding the short-channel effect in a conventional transistor.
As shown in FIG. 1, a structural diagram of an existing FinFET, comprising: a fin 100; a gate 102 on the upper surface and the sides of the fin: and a source/drain region 104 at two ends of the fin. The FinFET has the advantage of increased drive current, without taking much area, making it a promising competitor for the next generation Ultra-Large Scale Integration. Due to the three-dimensional device structure of the FinFET, in comparison with conventional planar technology, a new form of stress applying is required.
Therefore, it is desired to provide a method for manufacturing a FinFET, which can improve the effect of stress in the device and further improve the performance of the device.